Spring base for machines



INVENTOR RAY' W. P

Luw

R. W. PRESTON SPRING BA SE FOR MACHINES Filed Feb. 15, 1940 Aug. 13,1940.

ATTORNEY Patented Aug. 13, 1940 UNITED STATES PATENT OFFICE SPRING BASEFOR MACHINES 4 Claims.

This invention relates to a spring base for any machine where such abase will improve operation, such as typewriters, especially calculatingmachines, electric motors in small and medium sizes, etc.

An object of the present invention is a spring base that can be readilyadjusted over quite a wide range of 'weight supporting ability, withoutdiminishing its desirable characteristics.

Another object is a base that will utilize the resilient virtue of steelsprings without being resonant. Other objects, such as low cost,compactness and others that will be apparent from the specification andclaims attached, constitute the purposes of the invention, the scope ofwhich is to be ascertained from the claims.

To illustrate the invention, I have chosen the type that will beespecially useful for a computing machine, but this choice is made forpurposes of explanation and not for limitation.

A drawing accompanies and forms a part hereof, in which Fig. I is a topor plan view of a spring base for a computing machine;

Fig. II is an orthographic projection of Fig. I with a dotted outlinesuggesting the superposition of a computing machine;

Fig. III is an end-view, looking at the left-hand end of Fig. II;

Fig. IV is a section taken on IVIV, Fig. I; and

Fig. V is a section taken on V-V, Fig. IV.

In the drawing, I and 2 are identical return bends made of flat springmetal, preferably steel. They have loops 3, at one end, preferablyoffset as shown and the legs are, at least for the present embodiment,made of the same length. This form will be hereinafter referred to ashairpin bent, which is a widely used designation for pipes, springs andother things bent into the general form shown for various uses.

Pads such as 5, 6, l and 8 may be placed underneath the bottom of thelower leg and on top of the upper one, as shown in Fig. II if desired,and obviously the spread of the legs will be somewhat more without aweight, represented by the calculating machine, dotted, than with it.

Quite obviously the law of the lever will place practically all of thebending stress in the center of the loop in a hairpin bent spring ofequal cross section throughout, with very little deflection of the legmembers; hence were I to stop here each base would have to be made withextreme care for some machine of nearly exact weight, but I do not.

I form a rubber block that fits neatly within the loops such as 3 whenthe springs are open and without any weight. These blocks are indicatedby the numeral ID in Figs. IV and V, and follower plates II, having anoutline like the longitudinal section of the loop 3 but somewhat smallerare placed, one on each side of each block. Through bolts such as I2 areprovided with nuts, on the outside and inside of each plate such as M,l5, l6 and H, which will serve to compress the plates ll individuallyagainst the rubber blocks Ill, not only adjusting for height but alsofor level.

Since rubber, though having an extremely high modulus of elasticity, ispractically as incompressible as water when closely confined, I havehere an adjustment for my steel springs that will very considerablychange their weight carrying ability with a very small amount ofadjustment by the nuts such as l5, etc. The weak point, or that whichwill yield quickest if unsupported is the throat 3a. of the bend 3 nowbest supported.

When the weight is considerable, greater compression will result in therubber being forced out longitudinally between the legs of the spring asillustrated at l8, Fig. 11, which also has a marked effect on thestrength of the springs because here also the law of leverage controls.Rubber as used herein is intended to include natural rubber andcompounds thereof as well as synthetic substitutes having the resilientcharacteristics of natural rubber.

The through bolt l2, in this embodiment serves also as a distance pieceto give proper separation of the two spring members, as shown in Fig. I,but I prefer also to securely attach a thin plate, 20, to the lowermostlimb of the springs which adds a new and very desirable function,especially with a calculating machine, in that the operator can slip hisdata sheet under the machine as he works from column to column.

As indicated in the drawing, the plate 20 is not necessarily made of thesame size as the base of the machine served, but may be extended ateither or both sides or in front to provide a work holder ofconsiderable utility.

It will be noted that the ends of the hairpin bent springs shall nottouch, hence paper can be inserted from front as well as side. For basesintended for use as illustrated, on a table or the like, I prefer tomake the bends of the hairpin bent springs offset as shown so that evenwithout pads such as 5 and 6, the springs will lay flat on such asurface.

Having disclosed my invention in such a way that it will be clear tothose familiar with the art, what I claim is:

1. A spring base for a machine comprising a plurality of hairpin bentspring members, rubber filler blocks in the loops of the springs,follower plates on both sides of the filler blocks, screw means forcompressing the filler blocks by forcing the follower platesthereagainst and means for holding the hairpin bent springs in spacedrelationship to constitute a base of selected area.

2. A spring machine base of the character described comprising aplurality of hairpin bent springs the loops thereof being ofiset, rubberblocks in the loops, follower plates held against both sides of theblocks, means for compressing the follower plates against the rubberblocks to increase the resistance of the springs and means for rigidlyspacing the springs laterally from each other to comprise a base ofselected area:

3. A spring base for a machine comprising a plurality of hairpin bentspring members having legs of sufiicient length so that one leg of eachspring is adapted to form a part of the machine supporting structurewhile the other is adapted to rest on a support means, and means foradjusting the carrying capacity of the hairpin bent spring memberscomprising a rubber block fitted into the bent portions thereof andmeans for selectively compressing the rubber as required.

4. A spring for a machine base comprising a hairpin bent spring member,at least the loop of which is flattened on the inside, a rubber blockfitted within the loop, follower plates on both sides of the rubberblock and screw means for compressing the follower plates against therubber block to change the carrying capacity of the legs of the hairpinbent spring.

RAY W. PRESTON.

